The Friends of Science answers many questions from our readers. Here are some samples:

Question:

There is another website that supposedly provides evidence that humans are causing global warming and debunks the data presented by Friends of Science. I am still inclined to believe the data as presented by FoS, but could you direct me to data that disprove those on this below website? http://www.skepticalscience.com/empirical-evidence-for-global-warming.htm

FoS Response:

1. We're raising CO2 levels: This is true, but this is not evidence that CO2 has caused any warming.2. CO2 traps heat: This is true, but this is not evidence that the increase in CO2 has caused any warming. IF water vapour and clouds did not change in response to CO2, then the increase would cause warming, BUT water vapour and clouds change with increasing CO2 to keep the strength of the greenhouse effect constant. If fact, there has been no increase in the heat trapping ability of greenhouse gases in the atmosphere over the last 60 years according to the NOAA radiosonde (weather balloon) data, so there has been no increase in the effective amount of greenhouse gases in the atmosphere over that period. Also, clouds change in response to warming to allow more heat to be released to space.3. The planet is accumulating heat: This was true from 1979 to 2002, but is not true this decade. Since 2003 a set of 3340 automated bouys have been accurately measuring ocean heat content, and it has been falling significantly. The fact of accumulating heat to 2002 is not evidence that CO2 caused that heat accumulation. The fact that temperatures increased 1979 to 2002 tells us nothing of the cause.

The issues discussed in point 2 and 3 above are discussed in our Climate Change Science essay here. The Anthropogenic Greenhouse Effect is discussed in several articles in our Climate >>The Greenhouse Effect section here. Also see the Water Vapour Feedback section of our essay here, and a recent technical paper here. Clouds are discussed in the Cloud Feedback section of the essay here. Also see a more detailed discussion here, and two technical papers in the Climate Science >> Climate models section here and here. The falling heat content is discussed in the Climate Models Fail section of the essay here. Also see this paper in the Climate Science >> Oceans section.

AGW supporters fail to ask the obvious question: "What limits water vapour in the atmosphere above clouds to its current amount?" At current concentrations, a 3% change in water vapour has the same effect as a 100% change in CO2. The strength of the greenhouse effect is largely determined at the top of the atmosphere where the water vapour content is very low and radiation can escape without being recaptured. But in the upper atmosphere, the humidity is always much less the saturated value, so the amount of water vapour is not determined by the saturation limit. Instead, it is determined by the energy fluxes of the greenhouse effect, which is determined by the total greenhouse gases. It follows that there must be a total greenhouse gas limit determined by energy. That is why the amount of water vapour is limited to only 36% relative humidity at 8 km altitude, even though there is an infinite supply of water vapour from the oceans. If nature could have increased the greenhouse effect it would have done so billions of years ago with water vapour.

Question:

I'm curious as to why the line of best fit on your graph "Global Lower Troposphere Temperatures" on the home page was only drawn from 2002 onward. Certainly the issue of climate change incorporates more than the last 5 years? If the line of best fit was drawn for the span of '85-'89 it would show opposite results, as it would if you drew the line of best fit for the entire graph. I'm just curious for your justification for selecting only this period of time.

FoS Response:

The best fit line is shown from 2002+ for three reasons:

It draws your attention to the fact that global temperatures have been stable or declining since the beginning of 2002.

It indicates that the trend has changed from increasing to decreasing.

It allows a calculation of the rate of temperature change over the period.

The only constant about climate is that it changes, and therefore the trend will change. The FOS position based on science is that the Sun is the primary driver of climate change. The temperatures have increased from 1979 through 2002 primarily due to changes in the Sun. The Sun has been increasing in intensity and magnetic influence during most of the 20th century. There is some controversy over how much the Sun's irradiance has increased since 1980, but the ACRIM data shows increasing intensity after 1980. Since 1980 or 1990 there has been no increase, and the Sun has become very quiet. However, due to the huge heat capacity of the oceans, the Sun would continue to cause warming for about 2 decades after its intensity become constant or starts to decline.

The Sun's intensity is now falling, so we are now in a cooling phase. We believe that temperatures will not increase in spite of increasing CO2 emissions, which have only a minor effect on temperatures.

A trend line through the global temperature graph from 1979 to 2007 would show an increasing trend of +0.157 Celsius/decade. However, this is misleading for two reasons:

Volcanic eruptions causing two cool period on the left side of the graph, and the El Nino of 1998 on the right side of the graph, events which have nothing to do with the climate change trends, would tend to exaggerate the calculated warming trend.

A straight line through all the data would falsely imply that you should expect temperatures to continue on that trend, and it obscures that fact that the Sun's climate forcing has changed, causing a change in the trend.

Question:

Scientists around the globe agree that not only is the planet warming at an alarming rate, but also that this warming IS caused by humans (says the IPCC). Why shouldn't I believe them?

FoS Response:

Sorry, they don't, and it isn't. Literally tens of thousands of scientists have signed the Leipzig, Heidelberg and Oregon declarations/statements/petitions, protesting the abuse of the science and the politicised goings-on at the UN's IPCC. It is well established in science literature (though not in the excited media) that the longer term average rate of temperature increase is at about 0.8 C/ 100 year. Sometimes more, sometimes less. Remember the Global Cooling scare (1940-1980)? "Return to Snowball Earth!", papers screamed. At that time CO2 levels were increasing rapidly and the temperatures dropped.

There is a disconnect between CO2 and Temp. The function of CO2 as a driver of GW is distinctly minor in comparison to the variable Solar Radiation and cloud cover as influenced by Cosmic Rays. The references by Soon, Baliunas, Veizer and others are on our website. Increased solar flare activity will warm the planet, including the oceans, which can then hold less CO2 in solution and expel some, increasing the atmospheric CO2 content.

The IPCC considers only man-made causes of global waming.

Question:

The north pole's ice cap has considerably reduced over this period and that it will soon be possible to navigate through the North-West passage (which wasn't possible during the Medieval Warm period). Doesn't this indicate CO2 global warming?

FoS Response:

The North Pole does not have an "ice cap" only floating rotating and shifting sea ice. Changes in the Greenland cap are like all glaciers and all ice caps over time. There is nothing unnatural about it. During the Medieval Warm Period it was even warmer and the Vikings farmed on Greenland. Incidentally while the fringes are melting, the central ice packs (both Arctic and Antarctic) are growing as measured by satellite (due to precipitation). It means that the ice packs are alive and healthy: fed at the top and excreting at the bottom. In Antarctica, only the small Palmer Peninsula is melting because of ocean currents. Tha Antarctica overal temperatures have been declining over the last 50 years and its ice cap has been gaining mass due to precipitation.